Ultras are a type of association football fans who are renowned for their fanatical support. The term originated in Italy, but is used worldwide to describe predominantly organised fans of association football teams. The behavioural tendency of ultras groups includes singing football chants, playing musical instruments such as drums, their use of flares and smoke bombs, frequent use of elaborate displays, vocal support in large groups and the displaying of flags and banners at football stadiums, all of which are designed to create an atmosphere which encourages their own team and intimidates the opposing players and their supporters. These groups also commonly organise trips to attend away games.

A fandom is a subculture composed of fans characterized by a feeling of camaraderie with others who share a common interest. Fans typically are interested in even minor details of the objects of their fandom and spend a significant portion of their time and energy involved with their interest, often as a part of a social network with particular practices, differentiating fandom-affiliated people from those with only a casual interest.